Maintaining update

• Update engine Golang (1.19 -> 1.20)

Minor updates

• Change main module
• Update module client_golang (v1.13.0 -> v1.14.0)
• Improve documentation

Maintaining updates

• Update engine Golang (1.18 -> 1.19)
• Update module prometheus/client_golang (1.12.2 -> 1.13.0)

Minor updates

• Improve function for handling health check (#3)
• Update PromClient library (v1.12.1 -> v1.12.2) (#4)

Update dependencies

• Update Golang to 1.18
• Update all dependencies
• Fix missing library
• Change Docker base image (Alpine -> Scratch)